Logan Paul mocked Floyd Mayweather's size as the unlikely rivals faced off ahead of their exhibition bout.
The YouTube star and the ring legend will clash over six rounds on June 6 in Miami in a bout which could earn Mayweather up to $100million.
The pound-for-pound great will however have to give up a size and reach advantage with Paul standing 20cm taller. The social media star will also be allowed a 20lb weight advantage for the fight.
The opponents almost clashed prematurely when Mayweather ran into Paul on his way to the stage before being bundled back into his dressing room.
"I went out there; they said it was time for me to walk but Logan Paul was walking so they pushed me back," said Mayweather.
And when they did come face to face, Paul said: "I think you've bitten off more than you can chew. Why come out of retirement just to get re-retired."
Mayweather added: "We're going to come out, entertain and have fun.
"It's a fight for him but for me it's all about fun.
"The last time I fought in an exhibition in Japan it was only two minutes, hopefully this time it will be a bit longer.
"I've been here so many times and I just know what it takes."
Paul has fought just once as a 'professional', losing to rival KSI in a rematch of their white-collar bout which was scored a draw.
Mayweather last fought in 2018 when he knocked out kickboxing star Tenshin Nasukawa in the first round of their exhibition.
His last professional fight was a 10th-round stoppage of Conor McGregor in 2017 which took Mayweather's record to 50-0.